Organophosphorus compounds are as a group one of the most widely-used insecticides in agriculture. The pyridinyl phosphorus insecticides are a highly active group of compounds used for the kill and control of a great variety of insects.
It has been found, however, that certain pyridinyl phosphorus insecticides are not highly effective in the kill and control of insects of the order Lepidoptera and especially of the genus Heliothis. The reasons for the ineffectiveness of these pyridyl phosphorus insecticides are not fully known nor understood. It is believed that by some mechanism, insects from the above group are insensitive to these phosphorus compounds. Since these insects are of economic importance, methods are continually being sought to increase the activity of these insecticides in the control of insects of the order Lepidoptera.